Robotic medical devices have many advantages during medical procedures. (As used herein, the terms “robotic” or “robotically” and the like include teleoperation or telerobotic aspects.) In particular, computer control in a robotic medical device may be able to provide steadier and more precise movement of a tool such as a biopsy needle, scalpel, or clamp. For minimally invasive medical procedures, computer control may also facilitate miniaturization of a tool because the mechanical systems in the tool do not need to be easily hand operable or need to operate intuitively because computerized control systems can adapt to complex or obtuse mechanical systems or interfaces and still provide a human operator with a user interface that is easy to use.
One difficulty for robotic medical devices and their user interfaces is providing human personnel with haptic or tactile feedback. In particular, providing an input device of a computerized system with haptic feedback that is similar or equivalent to the haptic feedback of a manually manipulated medical instrument can be difficult. One example of a situation in which haptic feedback is important is during navigation of an instrument such as a lung catheter, a bronchoscope, a biopsy instrument, or other similar medical device through airways or other branching or convoluted natural lumens. In particular, insertion of an instrument through an airway may experience a challenge that increases resistance to further advancement of the instrument. The tip of the instrument may, for example, need to be reoriented where an airway bends or forks. The haptic or tactile feel that a doctor or other medical practitioner may receive from manually applying insertion pressure gives the practitioner guidance and insight regarding the interaction of the instrument with the airway. The practitioner may then be able to better judge whether or how to further advance the instrument, for example, by applying more insertion force, applying a torque or twist to reorient the instrument and reduce the friction in the airway, or partially or fully retracting the instrument. Haptic feel can be an important or critical factor that the practitioner uses during such decisions. However, standard robotically controlled instrument insertion techniques may provide the practitioner with no, little, or inaccurate tactile or haptic feedback.